A variety of implantable medical devices are used to treat portions of the anatomy which reside near bones or bony structures within the body of a patient. Such devices are typically anchored in place by suturing portions of the device to surrounding soft tissue. Often the device includes suture holes designed specifically for this purpose at predetermined locations along the device. Thus, the device may only be sutured at these locations, limiting the areas and types of tissue available for suturing thereto. Often, the location is far from the treatment site. Such distance and instability of anchoring tissue can contribute to lead migration and pull-out.
For example, conventional spinal cord stimulators (SCS) are positioned along the spinal column to treat pain. A conventional SCS system comprises an implantable lead and an implantable power source or implantable pulse generator IPG. Using fluoroscopy, the lead is implanted into the epidural space of the spinal column and positioned against the dura layer of the spinal cord. The lead extends from the spinal column to the IPG which is remotely implanted. Typically, the lead is sutured to soft tissue remote from the point of entry into the epidural space. And, lead migration and pull-out are common problems associated with SCS.
Therefore, it is desired to provide a more stable anchoring system for implantable devices, such as leads. Such an anchoring system should provide anchoring at desired locations rather than merely at locations along the device which are predesigned for anchoring. Such anchoring should also assist in resisting migration and pull-out. At least some of these objectives will be met by the present invention.